| 摘要 |
A fastener structure is formed by swaging groove cutting or self-tapping ribs or threads in the wall of an aperture, so the ribs will cut a groove or grooves in a stud rotated in the aperture. The walls surrounding the aperture are first deformed to provide helicoidal surfaces bordering the end of the aperture, and the wall is then swaged from the inclined edge to form a rib or thread from each surface of uniform height, or tapering in height according to the angle of the helicoidal surfaces.
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